[RFC PATCH v2 14/29] ntsync: Introduce NTSYNC_IOC_MUTEX_READ.

Elizabeth Figura
2024-01-31T02:16:03Z

This corresponds to the NT syscall NtQueryMutant().

This returns the recursion count, owner, and abandoned state of the mutex.

Signed-off-by: Elizabeth Figura <zfigura@codeweavers.com>
---
drivers/misc/ntsync.c | 23 +++++++++++++++++++++++
include/uapi/linux/ntsync.h | 1 +
2 files changed, 24 insertions(+)

diff --git a/drivers/misc/ntsync.c b/drivers/misc/ntsync.c
index 6dccfbfb2512..7f5f96ec7c69 100644
--- a/drivers/misc/ntsync.c
+++ b/drivers/misc/ntsync.c
@@ -525,6 +525,27 @@ static int ntsync_sem_read(struct ntsync_obj *sem, void __user *argp)
return 0;
}

+static int ntsync_mutex_read(struct ntsync_obj *mutex, void __user *argp)
+{
+ struct ntsync_mutex_args __user *user_args = argp;
+ struct ntsync_mutex_args args;
+ int ret;
+
+ if (mutex->type != NTSYNC_TYPE_MUTEX)
+ return -EINVAL;
+
+ args.mutex = 0;
+ spin_lock(&mutex->lock);
+ args.count = mutex->u.mutex.count;
+ args.owner = mutex->u.mutex.owner;
+ ret = mutex->u.mutex.ownerdead ? -EOWNERDEAD : 0;
+ spin_unlock(&mutex->lock);
+
+ if (copy_to_user(user_args, &args, sizeof(args)))
+ return -EFAULT;
+ return ret;
+}
+
static int ntsync_obj_release(struct inode *inode, struct file *file)
{
struct ntsync_obj *obj = file->private_data;
@@ -550,6 +571,8 @@ static long ntsync_obj_ioctl(struct file *file, unsigned int cmd,
return ntsync_mutex_unlock(obj, argp);
case NTSYNC_IOC_MUTEX_KILL:
return ntsync_mutex_kill(obj, argp);
+ case NTSYNC_IOC_MUTEX_READ:
+ return ntsync_mutex_read(obj, argp);
case NTSYNC_IOC_EVENT_SET:
return ntsync_event_set(obj, argp, false);
case NTSYNC_IOC_EVENT_RESET:
diff --git a/include/uapi/linux/ntsync.h b/include/uapi/linux/ntsync.h
index 6017f621687e..a1d0ef581212 100644
--- a/include/uapi/linux/ntsync.h
+++ b/include/uapi/linux/ntsync.h
@@ -52,5 +52,6 @@ struct ntsync_wait_args {
#define NTSYNC_IOC_EVENT_RESET _IOR ('N', 0x89, __u32)
#define NTSYNC_IOC_EVENT_PULSE _IOR ('N', 0x8a, __u32)
#define NTSYNC_IOC_SEM_READ _IOR ('N', 0x8b, struct ntsync_sem_args)
+#define NTSYNC_IOC_MUTEX_READ _IOR ('N', 0x8c, struct ntsync_mutex_args)

#endif
--
2.43.0